Self-sealing envelope



W HOHWART SELF-SEALING ENVELOPE Flled March 17, 1936 Patented May 9, 1939 SELF-SEALING ENvEhorE William Hohwart, New York, n. a. Application -March 17, 1936, Serial No. 69,255 4, Claims. (01. 229-86) This invention relates to an improved envelope having sealing means which'will seal itself on the application of pressure, without the aid of water or any other moistening agent, and which is normally protected against accidental sealing.

It is well known that envelopes having a sealing flap coated with a mucilage of the type which contains gelatine or gum arable will soften in the presence of heat or moisture, and that the sealing flaps will become sealed before being filled for mailing, because such flaps are in normalcontact with the body of the envelope and when the adhesive material is softened either by heat. or by moisture arising from rain, excessive humidity,--or steam, or leakage, the envelopes are ruined by this sealing action in advance of mailing.

Envelopes of this type, having adhesive material composed of either animal or vegetable gums are also attacked by insects, which devour the adhesive material. I

Such envelopes when passed through the mails in their normal sealed condition can be opened by steaming the adhesive, and-the contents removed or unlawfully inspected.

The object of the present invention is to provide an envelope which will not soften-in the presence of heat or moisture, or otherwise become accidentally sealed, and which can be sealed only by placing two cooperating sealing layers of a latex adhesive in contact with each other, by folding the outer sealing flap against asurface normally protected by an inner sealing flap, of special construction. I

Another object of the invention is to provide an envelope with an inner sealing flap which normally protects the inner layer or coat of latex adhesive, and an outer sealing flap which folds over the inner sealing flap, with thelower longitudinal edge of the inner sealing flap projecting slightly from the corresponding edge of the' outer sealing flap, so that the two flapscan be shifted to open position without confusion, by a single hand movement, to permit of the insertion of mailing'matter in the envelope and to insure that when the outer sealing flap islclosed for mailing that it will adhere'by manual pressure to the exposed inner surface of the inner flap, thereby sealing the envelope without the aid of moisture or heat.

Another object of the invention is to. provide the sealing flap of such anenvelope with weakening lines, which will'cause the sealing flap to break if any attempt is made to tamper with the sealing flap.

With the above and other objects in'view the.

I rows, but greatlymagnifled.

invention consists in certain new and useful constructions, combinations and arrangements of parts, clearly described in the following specifica-- tions, and fully illustrated in the drawing, in which Fig. 1 is a plan view showing theenvelope in its normal condition.

Fig. 2 is a plan view showing the sealing and inner flaps extended to open positions.

Fig. 3 is a vertical sectional view, taken on line 3-3 of Fig. 1, looking in the direction of the arrows.

Fig. 4 is a similar view, showing the inner flap in its sealing position. Fig. 5 is a vertical sectional view, taken on line 5-5 of Fig. 2, looking in the direction of the ar-' rows.

Fig. 6 is a detail sectional view, taken on line 6-6 of Fig. 2, looking in the diretcion of the ar- Referring to the drawing illustrating the. invention, 5 designates the face wall, 6 the main back wall, I and 8 the end connecting flaps, which unite the 'main back wall flap to the face wall. I

Theupper longitudinal edge of the main back 5 wall 6 is formed with an inner flap 9, which is normally folded. against the outer surface of -the back wall, and which. is provided with alongitudinal outer edge 9a, which' -is parallel to the bending line ma of the outensealing flap 3,30 which folds on the upper longitudinal edge of the face-wall 5, to largely cover the inner flap, leaving only a'narrow, pickable edge exposed to direct observation.

The inner surface of the sealing flap is formed with a strip layer" of latex adhesive ll, disposed in parallel relation to the outer longitudinal edge thereof. This strip layer of latex adhesive cannot be made sticky .or tackyby'the addition'oi moisture or heat and is in normal engagement 40 with the outer surface '92) of the innerflap, and because of its physical and chemical nature will not adhere to this uncoated surface. v y The back wall 6 is formed with another cooperating strip layer l2, which is normally protected by the inner flap 9, which in its folded po sition lies against the back wall and completely covers and thus separates the inner strip layer I? of latex adhesive from the outer strip layer ll of adhesive of the same characteristics, carso ried by the sealing flap.

The construction of the envelope is such'that when the inner flap is opened the. outer flap will i also be opened. It the mailing matter is then inserted in the envelope and the sealing flap is fold- -improved with age.

ed against the back wall, the strip layer of adhesive carried by the sealing flap will be brought into direct engagement with the innerstrip layer of latex adhesive.

When this is done the sealing flap will be securely sealed, without theme of water or other moistening or softening agent. To protect the sealing flap against unlawful interference I may provide a. series of weakening lines or perforations l3, formed in the stock of the sealingenvelope, and preferably against the innerface thereof, so as to not entirely pierce the flap and to be largely concealed when the sealing flap is closed. When an effort is made to lift the sealing flap, without detection, these weakening lines will cause the sealing flap to readily tear, thus revealing the fact that the envelope has been tampered with.

The latex adhesive contains a preservative of ammonia which prevents disintegration, and is not attacked by insects in warm climates. It is normally not sticky, and will not adhere to the 'fingers of the user of the envelope.

When the envelopes are employed by persons whose fingers are slightly oily, the inner flap may may raise both the inner and other or outer flaps.

The. latex adhesive has the unusual quality-of adhering instantly only -to -a latex covered surface, by manual pressure' without the aid of any moistening agent. This instant adhesion insures complete sealing, because it is always. easy to ap ply external pressure. when the two strip layers of the latex adhesive are brought into physi contact with each other, and when no sof is required the latex surfaces are always ready for effective sealing action against each other:

The incisions or: weakingcuts in the inner surface of the outer sealing flap also insure penetration of the latex adhesive,le'aving the externail surface of the sealing flap unbroken.

The improved envelope when sealed by manual pressure only will not loosen or soften when immersed or exposed to water, steam, vapor or dampness, or when exposed to unusual heat. Under these conditions the envelope will preserve its shape and hold its contents.

The construction of the envelope-is such that it can be used in the manner conventionally employed in connection with standard envelopes ing action of moisture.

The connecting flaps are preferably sealed to the back flaps by the use of latex adhesive, and this makes the entire envelope weather proof. It is found by time'tests that the latex adhesive 7 It does not soften in the presence of moistureor steam, and will not dis- -color the paper. It is progressively absorbed by along one side and provided-with an inner proraper and water-proofs the paper where it penetrateathus insuring a' sealing action which cannot be weakened by the application of water, steam or other softening agencies."

Having described my invention 1 claim as new: 1. A self-sealing envelope comprising a face wall, a back wall connected thereto and open tective fiap and a strip of latex adhesive located on the outer surface of the back wall and protected normally by the inner protective flap which'is folded against the back well, said inner protective flap folding on the upper edge of the back wall to an open position to expose said strip of latex adhesive, and a sealing flap on the face I f a pickable edge, whereby both flaps may be turned from closed to open position by lifting the inner r 2. In an envelope, a front wall having a normally downturned sealing flap at its upper edge provided with an area of dry-sealing adhesive on the undersurface thereof adjacent its free edge, a rear envelope wall having its upper edge terminating in spaced relation to the upper edge of the front wall with an area of. dry-sealing adhesive on the outer surface thereof located so as to cooperatively interseal with the adhesive area of the front wall flap, and a normally downturned flap at the upper edge of the rear wall adapted to cover the adhesive area to underlie the front wall flap and when swung upwardly into the plane of the rear wall to expose the adhesive area thereof-for cooperative sealing with the adhesive area of the front wall flap, the free flap protruding beyond the edge of said rear wall front wall flap and constituting means for facilitating the simultaneous raising of both flaps during the operation of sealing the envelope.

3. In an envelope, a front wall having a normally downturned sealing flap at its upper edge provided on its undersurface with an area of y sealing adhesive, a rear envelope wall having an area of dry sealing adhesive on the outer surarea thereof and adapted to be swung to an outof-the-way position to expose said adhesive area for cooperative sealing with the adhesive area of the front wall flap, thefree edge of said rear wall flap, projecting beyond the front wall flap to serve as a means for facilitating the simultaneous raising of both flaps from their normal downturned position. I

4. In an envelope, a front wall having a normally downturned sealing flap at its upper edge provided on its undersurface with an area of dry sealing adhesive, a rear envelope wall having an area of dry sealing adhesive on the outer surface thereof located so as to cooperatively interseal with the adhesive area of the front' wall flap, and a normally downturned flap carried by the rear wall adapted to normally cover the adhesive area thereof and'adapted to be swung to an out of the way position 'to expose said adhesive area for cooperative sealing with the adhesive area of the front wall flap, the free edge ofsaid rear wall flap projecting beyond the front wall flap to serve asa means for facilitating the simultaneous raising of both flaps from their normal downturned position, the portions of the envelope provided with the areas of dry sealing adhesive having superficial cuts in the surface underlying the adhesive as and for the purpose set 

